1 files changed, 89 insertions, 8 deletions

diff --git a/drivers/thermal/intel/intel_hfi.c b/drivers/thermal/intel/intel_hfi.c
index 40d664a66cdc..fbc7f0cd83d7 100644
--- a/drivers/thermal/intel/intel_hfi.c
+++ b/drivers/thermal/intel/intel_hfi.c
@@ -159,6 +159,7 @@ struct hfi_cpu_info {
 static DEFINE_PER_CPU(struct hfi_cpu_info, hfi_cpu_info) = { .index = -1 };
 
 static int max_hfi_instances;
+static int hfi_clients_nr;
 static struct hfi_instance *hfi_instances;
 
 static struct hfi_features hfi_features;
@@ -477,8 +478,11 @@ void intel_hfi_online(unsigned int cpu)
 enable:
 	cpumask_set_cpu(cpu, hfi_instance->cpus);
 
-	/* Enable this HFI instance if this is its first online CPU. */
-	if (cpumask_weight(hfi_instance->cpus) == 1) {
+	/*
+	 * Enable this HFI instance if this is its first online CPU and
+	 * there are user-space clients of thermal events.
+	 */
+	if (cpumask_weight(hfi_instance->cpus) == 1 && hfi_clients_nr > 0) {
 		hfi_set_hw_table(hfi_instance);
 		hfi_enable();
 	}
@@ -573,18 +577,33 @@ static __init int hfi_parse_features(void)
 	return 0;
 }
 
-static void hfi_do_enable(void)
+/*
+ * If concurrency is not prevented by other means, the HFI enable/disable
+ * routines must be called under hfi_instance_lock."
+ */
+static void hfi_enable_instance(void *ptr)
+{
+	hfi_set_hw_table(ptr);
+	hfi_enable();
+}
+
+static void hfi_disable_instance(void *ptr)
+{
+	hfi_disable();
+}
+
+static void hfi_syscore_resume(void)
 {
 	/* This code runs only on the boot CPU. */
 	struct hfi_cpu_info *info = &per_cpu(hfi_cpu_info, 0);
 	struct hfi_instance *hfi_instance = info->hfi_instance;
 
 	/* No locking needed. There is no concurrency with CPU online. */
-	hfi_set_hw_table(hfi_instance);
-	hfi_enable();
+	if (hfi_clients_nr > 0)
+		hfi_enable_instance(hfi_instance);
 }
 
-static int hfi_do_disable(void)
+static int hfi_syscore_suspend(void)
 {
 	/* No locking needed. There is no concurrency with CPU offline. */
 	hfi_disable();
@@ -593,8 +612,58 @@ static int hfi_do_disable(void)
 }
 
 static struct syscore_ops hfi_pm_ops = {
-	.resume = hfi_do_enable,
-	.suspend = hfi_do_disable,
+	.resume = hfi_syscore_resume,
+	.suspend = hfi_syscore_suspend,
+};
+
+static int hfi_thermal_notify(struct notifier_block *nb, unsigned long state,
+			      void *_notify)
+{
+	struct thermal_genl_notify *notify = _notify;
+	struct hfi_instance *hfi_instance;
+	smp_call_func_t func = NULL;
+	unsigned int cpu;
+	int i;
+
+	if (notify->mcgrp != THERMAL_GENL_EVENT_GROUP)
+		return NOTIFY_DONE;
+
+	if (state != THERMAL_NOTIFY_BIND && state != THERMAL_NOTIFY_UNBIND)
+		return NOTIFY_DONE;
+
+	mutex_lock(&hfi_instance_lock);
+
+	switch (state) {
+	case THERMAL_NOTIFY_BIND:
+		if (++hfi_clients_nr == 1)
+			func = hfi_enable_instance;
+		break;
+	case THERMAL_NOTIFY_UNBIND:
+		if (--hfi_clients_nr == 0)
+			func = hfi_disable_instance;
+		break;
+	}
+
+	if (!func)
+		goto out;
+
+	for (i = 0; i < max_hfi_instances; i++) {
+		hfi_instance = &hfi_instances[i];
+		if (cpumask_empty(hfi_instance->cpus))
+			continue;
+
+		cpu = cpumask_any(hfi_instance->cpus);
+		smp_call_function_single(cpu, func, hfi_instance, true);
+	}
+
+out:
+	mutex_unlock(&hfi_instance_lock);
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block hfi_thermal_nb = {
+	.notifier_call = hfi_thermal_notify,
 };
 
 void __init intel_hfi_init(void)
@@ -628,10 +697,22 @@ void __init intel_hfi_init(void)
 	if (!hfi_updates_wq)
 		goto err_nomem;
 
+	/*
+	 * Both thermal core and Intel HFI can not be build as modules.
+	 * As kernel build-in drivers they are initialized before user-space
+	 * starts, hence we can not miss BIND/UNBIND events when applications
+	 * add/remove thermal multicast group to/from a netlink socket.
+	 */
+	if (thermal_genl_register_notifier(&hfi_thermal_nb))
+		goto err_nl_notif;
+
 	register_syscore_ops(&hfi_pm_ops);
 
 	return;
 
+err_nl_notif:
+	destroy_workqueue(hfi_updates_wq);
+
 err_nomem:
 	for (j = 0; j < i; ++j) {
 		hfi_instance = &hfi_instances[j];